Flexible couplings are used to connect and transmit power between rotating shafts. A flexible coupling of the toothed shear-type comprises a flexible element, typically elastomeric, that couples non-overlapping teeth of two adjacent radially aligned shaft hubs. A short gap between the teeth of the hubs allows clearance for a degree of angular misalignment.
In fact, under load such couplings apply a significant amount of compression to the teeth, thereby making them act as xe2x80x9ccombination shear and compressionxe2x80x9d couplings. Compared to other types of flexible shear-type couplings, they exert as much as fifty percent more axial thrust load on the coupled shafts, thereby increasing the shaft bearing axial load and bearing wear.
According to the invention, a toothed shear-type flexible coupling has clearance provided between the hub faces and the tooth faces of the flexible element to prevent significant axial thrust loading from being transmitted to the hubs under load. Small centring tabs are added on the hub faces between the hub teeth to align the flexible element between the hubs. Axial thrust loading is minimised by changing its primary source from one due to twisting of the flexible element and contact on the hub faces to compression of the element and contact on the tab faces.
According to one embodiment of the invention, a flexible coupling has a generally cylindrical flexible element with a plurality of generally radial element teeth that are engaged by a plurality of generally radial hub teeth that penetrate generally radial element tooth faces on the element teeth, with the hub teeth arranged around generally radial hub faces of generally cylindrical shaft hubs and means for reducing axial loading of drive shafts attached to the hubs under load that comprises a plurality of generally radial centring tabs arranged around the hub faces between the hub teeth, the tabs having generally radial tab faces that contact the element tooth faces.